Bioaccumulation and lack of oxidative stress response in the ragworm H. diversicolor following exposure to Ra in sediment

The main effluent from oil and gas production, produced water, from some platforms in the North Sea contains elevated concentrations of ²²⁶Ra. The aim of this study was to investigate whether ²²⁶Ra in sediment would accumulate in and affect sediment-dwelling organisms. In addition, we wanted to determine if the bioavailability would be modulated by the presence of a scale inhibitor which is used during oil and gas production. Hediste diversicolor was therefore exposed to different levels of ²²⁶Ra (30–6600 Bq kg⁻¹) in combination with scale inhibitor in the sediments in a flow through system. The levels of radioactivity in the exposures were close to levels that can be measured in proximity to oil/gas production facilities. ²²⁶Ra spiked to natural sediment partitioned into pore water and accumulated in the sediment-dwelling polychaete following a four-week exposure period. The results suggest that ²²⁶Ra did not bind strongly to sediment (low sediment:water partitioning coefficient), but it was not shown to bioaccumulate in any great extent (bioaccumulation factors of 0.019–0.022). Exposure of H. diversicolor in sediments with up to 6600 Bq kg⁻¹²²⁶Ra had no measurable effect on the total oxyradical scavenging capacity of the organisms compared to control. So although they accumulated the alpha-emitter, the treatments did not appear to cause oxidative stress in polychaete tissues.     

Improving Oxygen Conditions in the Deeper Parts of Bornholm Sea by Pumped Injection of Winter Water

Vertical diffusivity and oxygen consumption in the basin water, the water below the sill level at about 59 m depth, have been estimated by applying budget methods to monitoring data from hydrographical stations BY4 and BY5 for periods without water renewal. From the vertical diffusivity, the mean rate of work against the buoyancy forces below 65 m depth is estimated to about 0.10 mW m⁻². This is slightly higher than published values for East Gotland Sea. The horizontally averaged vertical diffusivity κ can be approximated by the expression κ = a₀N⁻¹ where N is the buoyancy frequency and a₀ ≈ 1.25 × 10⁻⁷ m² s⁻², which is similar to values for a₀ used for depths below the halocline in Baltic proper circulation models for long-term simulations. The contemporary mean rate of oxygen consumption in the basin water is about 75 g O₂ m⁻² year⁻¹, which corresponds to an oxidation of 28 g C m⁻² year⁻¹. The oxygen consumption in the Bornholm Basin doubled from the 1970s to the 2000s, which qualitatively explains the observed increasing frequency and vertical extent of anoxia and hypoxia in the basin water in records from the end of the 1950s to present time. A horizontally averaged vertical advection–diffusion model of the basin water is used to calculate the effects on stratification and oxygen concentration by a forced pump-driven vertical convection. It is shown that the residence time of the basin water may be reduced by pumping down and mixing the so-called winter water into the deepwater. With the present rate of oxygen consumption, a pumped flux of about 25 km³ year⁻¹ would be sufficient to keep the oxygen concentration in the deepwater above 2 mL O₂ L⁻¹.     

Ecology,evolution, and management strategies of northern pike populations in the Baltic Sea

Baltic Sea populations of the northern pike (Esox lucius) have declined since the 1990s, and they face additional challenges due to ongoing climate change. Pike in the Baltic Sea spawn either in coastal bays or in freshwater streams and wetlands. Pike recruited in freshwater have been found to make up about 50 % of coastal pike stocks and to show natal homing, thus limiting gene flow among closely located spawning sites. Due to natal homing, sub-populations appear to be locally adapted to their freshwater recruitment environments. Management actions should therefore not involve mixing of individuals originating from different sub-populations. We offer two suggestions complying with this advice: (i) productivity of extant freshwater spawning populations can be boosted by modifying wetlands such that they promote spawning and recruitment; and (ii) new sub-populations that spawn in brackish water can potentially be created by transferring fry and imprinting them on seemingly suitable spawning environments.     

Polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCD) in seven different marine bird species from Iceland

Data on distribution, concentration and trends of polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs) is scarce in biota from the sub-Arctic region of the Atlantic. The present study is an investigation on PBDE and HBCD concentrations in eggs from seven marine bird species from Iceland, i.e. common eider (Somateria mollissima), arctic tern (Sterna paradisaea), guillemot (Uria aalge), fulmar (Fulmarus glacialis), lesser black-backed gull (Larus fuscus), great black-backed gull (Larus marinus) and great skua (Stercorarius skua). Concentrations of sum PBDEs ranged from 44 ng g⁻¹ fat in eider eggs to 2400 ng g⁻¹ fat in great skua eggs. The contribution of different PBDE congeners to the sum concentration differed between species. Concentration of HBCDs (sum of α−,β⁻ and γ−HBCD) ranged from 1.3 ng g⁻¹ fat in arctic tern eggs to 41 ng g⁻¹ fat in great black-backed gull. PCA on PBDE and HBCD shows different trends between the two BFR groups, further indicating different sources/usage. Investigations on any potential health or population effects of environmental pollutants on the great skua are advised since both the PBDE and HBCD concentrations are high.     

Chemisorption of hydrogen sulphide and methanethiol by light expanded clay aggregates (Leca)

Removal of volatile sulphur compounds from livestock waste air by biological air filtration may be enhanced by application of packing materials with reactive properties. In this study, light expanded clay aggregates (Leca®) was tested with respect to sorption and potential chemical degradation of H₂S, Methanethiol (MT) and Dimethyl sulphide (DMS). Leca was selected due to its content of minerals, including iron, and due to its high specific surface area. The performance of Leca was evaluated based on breakthrough curves and by comparing the difference between the inlet and outlet gas concentrations. Whereas DMS did not appear to be removed by Leca, both H₂S and MT were removed with variable efficiency depending on the specific conditions. Dimethyl disulphide (DMDS) and dimethyl trisulphide (DMTS) were demonstrated to be produced during the degradation process in relatively high yields. A comparison between ambient air and nitrogen gas conditions showed that the chemisorption of H₂S and MT did not necessarily need oxygen to be present. X-ray analysis of Leca showed an abundance of Fe₂O₃. It is therefore hypothesized that Fe₂O₃ in Leca can remove H₂S and MT by chemisorption. Both air velocity and moisture content clearly affected the capacity of Leca for removal of H₂S and MT. Lower removal is seen at higher air velocities, whereas higher moisture content enhances removal. However, chemisorption of MT by Leca appears to be limited above a threshold moisture level. Potential reaction mechanisms are discussed in relation to the observed effects. The results implicate that Leca can be used as a filter material with reactive properties provided that moisture content is controlled and that an adequate air velocity is used.     

High prevalence of infections and pathological changes in burbot (Lota lota) from a polluted lake (Lake Mjøsa,Norway)

The aim of the present study was to investigate whether exposure to high levels of persistent organic pollutants (POPs) affected a fish population in Lake Mjøsa. Lake Mjøsa is known to be contaminated by polybrominated diphenyl ethers (PBDEs), a subgroup of brominated flame retardants from local industrial activities. Fish from Lake Losna, a less contaminated lake located close to Lake Mjøsa, was used as reference (control).The sampling of burbot (Lota lota) was carried out between 2005 and 2008. Hepatic levels of POPs were analysed in burbot from the two lakes, and the fish were examined for bacterial- and parasite infection and histopathological changes. The levels of polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethanes (DDTs), and PBDEs were about 10, 15 and 300 times higher in fish from Lake Mjøsa compared to fish from Lake Losna. Mycobacterium salmoniphilum was present in 7% and 35% of the fish from Lake Losna and Lake Mjøsa respectively. Significantly higher number of external and visceral macroscopic lesions, histopathological diffuse changes and granulomas were seen in fish from Lake Mjøsa compared to Lake Losna. Furthermore the parasite infection was higher and the hepatic lipid content was significantly lower in burbot from Lake Mjøsa. The results of the present study suggest that the high level of contamination in Lake Mjøsa could have a negative impact on the health status of wild fish inhabiting the lake.     

Linking Cellulose Fiber Sediment Methyl Mercury Levels to Organic Matter Decay and Major Element Composition

Methylation of mercury (Hg) to highly toxic methyl Hg (MeHg), a process known to occur when organic matter (OM) decomposition leads to anoxia, is considered a worldwide threat to aquatic ecosystems and human health. We measured temporal and spatial variations in sediment MeHg, total Hg (THg), and major elements in a freshwater lagoon in Sweden polluted with Hg-laden cellulose fibers. Fiber decomposition, confined to a narrow surface layer, resulted in loss of carbon (C), uptake of nitrogen (N), phosphorus (P), and sulfur (S), and increased MeHg levels. Notably, fiber decomposition and subsequent erosion of fiber residues will cause buried contaminants to gradually come closer to the sediment–water interface. At an adjacent site where decomposed fiber accumulated, there was a gain in C and a loss of S when MeHg increased. As evidenced by correlation patterns and vertical chemical profiles, reduced S may have fueled C-fixation and Hg methylation at this site.     

The Swedish monitoring of surface waters: 50 years of adaptive monitoring

For more than 50 years, scientific insights from surface water monitoring have supported Swedish evidence-based environmental management. Efforts to understand and control eutrophication in the 1960s led to construction of wastewater treatment plants with phosphorus retention, while acid rain research in the 1970s contributed to international legislation curbing emissions. By the 1990s, long-time series were being used to infer climate effects on surface water chemistry and biology. Monitoring data play a key role in implementing the EU Water Framework Directive and other legislation and have been used to show beneficial effects of agricultural management on Baltic Sea eutrophication. The Swedish experience demonstrates that well-designed and financially supported surface water monitoring can be used to understand and manage a range of stressors and societal concerns. Using scientifically sound adaptive monitoring principles to balance continuity and change has ensured long-time series and the capability to address new questions over time.     

Spatial Distribution of Particulates from Sugar Cane Fires in Hawaii: Measurements and Calculations

Since cotton today is machine picked, the mere process of ginning creates a significant amount of trash and dust. A large cotton gin in Fresno operating at 23 bales per hour uses two rotating filters to control this material. Total emissions from the facility are in the order of 50 pounds per hour, or about one-half the emissions from a typical gin using cyclones as control equipment.     

Improvement of Baltic proper water quality using large-scale ecological engineering

Eutrophication of the Baltic proper has led to impaired water quality, demonstrated by, e.g., extensive blooming of cyanobacteria during the premium summer holiday season and severe oxygen deficit in the deepwater. Sustainable improvements in water quality by the reduction of phosphorus (P) supplies will take several decades before giving full effects because of large P storages both in soils in the watershed and in the water column and bottom sediments of the Baltic proper. In this article it is shown that drastically improved water quality may be obtained within a few years using large-scale ecological engineering methods. Natural variations in the Baltic proper during the last decades have demonstrated how rapid improvements may be achieved. The present article describes the basic dynamics of P, organic matter, and oxygen in the Baltic proper. It also briefly discusses the advantages and disadvantages of different classes of methods of ecological engineering aimed at restoring the Baltic proper from eutrophication effects. Preliminary computations show that the P content might be halved within a few years if about 100 kg O2 s(-1) are supplied to the upper deepwater. This would require 100 pump stations, each transporting about 100 m3 s(-1) of oxygen-rich so-called winter water from about 50 to 125 m depth where the water is released as a buoyant jet. Each pump station needs a power supply of 0.6 MW. Offshore wind power technology seems mature enough to provide the power needed by the pump stations. The cost to install 100 wind-powered pump stations, each with 0.6 MW power, at about 125-m depth is about 200 million Euros.